The present invention relates to a method and apparatus for controlling an automated guided vehicle.
Automated guided vehicles have been put into practical applications in the field of Factory Automation, and have been greatly contributing to development of industries. In the field of office automation, an attempt is made to employ an automated guided vehicle to provide services associated with mails, office machines, tea serving, and the like. The present applicant has already developed an automated guided vehicle control system using a magnetic lattice guide lane developed for the office automation (5th International Conference on Automated L. Guided Vehicle Systems, 1987).
FIG. 1 shows an automated guided vehicle travel control system using a conventional lattice guide lane. In FIG. 1, the lattice guide lane consists of lattice guide markers X.sub.1 to X.sub.4 and Y.sub.1 to Y.sub.5, and the like obtained by spreading on a floor, in a matrix format, P-tiles in each of which a cross-, T-, or L-shaped magnetic marker is buried. Assuming that a vehicle 1 which goes along the guide marker Y.sub.1 and approaches a point S before a cross-point A with the guide marker X.sub.2 must go from the point A to a point E(X.sub.2,Y.sub.5) via a point C Y.sub.3), the travel operation is performed as follows in the conventional system. The vehicle 1 goes from the point A to a point B along the guide marker Y.sub.1 while detecting the magnetic marker by a magnetic sensor, temporarily stops at the point B, and then turns right in 90.degree.. The vehicle 1 then goes ahead along the guide marker X.sub.4, and reaches a point D via the point C. The vehicle 1 temporarily stops at this point D, turns right in 90.degree., and then goes along the guide marker Y.sub.5 to reach the point E.
The travel control described above is performed while being guided by the guide markers, and has an advantage in safety in that the vehicle does not easily overrun. However, since the vehicle must be temporarily stopped at a corner when it turns, a lead time is undesirably prolonged. Since the conventional vehicle has only one sensor (infrared sensor) for detecting a forward obstacle, it can avoid an already detected obstacle, or the like. However, the vehicle cannot travel while recognizing the presence/absence and size of an arbitrarily laid down obstacle and avoiding it.
When the traveling vehicle suddenly encounters an obstacle ahead, since a distance between the obstacle and the vehicle is small, the vehicle may collide against the obstacle while avoiding the obstacle by a right-angle turn. In addition, a vehicle basically travels straight, and performs a right-angle turn when it changes a direction. Therefore, a travel time for executing the avoiding operation is greatly prolonged.